Method and devices for monitoring subscribers of a telecommunications network during participation in group call connections

ABSTRACT

The invention relates to a gas-insulated bus bar component comprising a grounded housing that is filled with protective gas and at least one bus bar conductor, which extends in the longitudinal direction of the housing and is supported on said housing by means of insulating bus bar supports. According to the invention, each bus bar conductor is connected to a disconnecting switch that is insulated by protective gas. The aim of the invention is to provide a component of this type, which can be simply connected to and disconnected from an air-insulated conductor, even when operational. To achieve this, the disconnecting switch is located in an outdoor bushing that is fixed to the housing.

CLAIM FOR PRIORITY

This application is a national stage of PCT/EP2004/050921 which waspublished on Dec. 9, 2004 and which claims the benefit of priority toGerman Application No. 103 24 872.2 filed Jun. 2, 2003.

TECHNICAL FIELD OF THE INVENTION

It is known from mobile radio standards, such as 3G-TS33.107v3.0.0R1999(see www.etsi.org) that calls between two subscribers in a mobile radionetwork can be intercepted by government offices.

BACKGROUND OF THE INVENTION

In various mobile radio networks (GSM, CDMA 3G, TETRA or others) groupscall connections between more than two subscribers are known, in whichtraffic channels exist between at least one speaker and at least onelistener. Examples of group call connections are the Voice Group CallService (VGCS) according to 3GPP-TS-42.068 (according to whichspecification there is provision for speaking, listening, speaking andlistening subscribers as well as dispatchers (able to speak withoutvoice authorization tokens)) corresponding essentially to a specialconference mode and the Voice Broadcast Service (VBS) according to3GPP-TS42.069 (according to which voice data of a speaker is transmittedto a plurality of listeners in a predefined area (Voice Broadcast CallArea)) corresponding to a broadcast via one or a plurality of cellsand/or to predefined subscribers receiving the VBS.

SUMMARY OF THE INVENTION

The object of the present invention is to allow the most extensivemonitoring possible of subscribers in a telecommunication network in anefficient manner even when group call connections are used. The objectis achieved respectively by the subject matter of the independentclaims.

As according to the invention it is determined for the subscriberinitiating the setting up of a group call connection (a connectionbetween more than two subscribers) and for further subscribers in thegroup call connection, whether there is provision for interception and(if there is such provision for at least one of the subscribers in thegroup call connection) the voice data transmitted via the group callconnection is supplied to an interception equipment, more extensivemonitoring or interception of subscribers in a telecommunication networkis possible than with the prior art, as the prior art allows reliablemonitoring of originating connections (e.g. subscribers requesting thesetting up of the group call connection) but does not allow efficientmonitoring of terminating connections (subscribers participating in thegroup call as listeners).

To intercept voice data from/for subscribers in a group to be monitored(of which a subscriber to be monitored is part) efficiently, either acopy of the voice data transmitted via the group connection ispreferably transmitted in a switching center as a copy to a monitoringdevice (LEA) based on a group call ID or alternatively a monitoringdevice is included as a monitoring center (for example just as alistener or dispatcher) in the group connection (preferably without theother subscribers being able to discern this), i.e. extending the groupconnection to this end by one subscriber (the monitoring center MC).

It can be decided whether at least one subscriber in a group callconnection and therefore the group call connection as a whole (all thevoice data transmitted via said connection) is to be intercepted inparticular by interrogating a home location register or visitor locationregister of a mobile radio network that contains data relating to saidsubscriber.

Preferably only group call connections are intercepted in which at leastone subscriber to be monitored participates actively in the groupconnection, i.e. (in particular in response to a prompt) has requestedthe receipt of voice data and/or transmission of voice data(listener/talker/dispatcher) or automatically has such status for thisgroup call connection based on default settings. In mobile radionetworks groups of subscribers can be defined, the subscribers in whichcan participate in a group call connection (i.e. receive transmittedvoice data and/or transmit voice data via traffic channels), byresponding positively to a registration prompt for the group callconnection or by being provided for automatically for every group callconnection set up for this group. Subscribers in a group, who are notavailable locally or do not respond positively to a prompt toparticipate in a group connection, are expediently not switched to thetraffic channels of the group call connection until they do so (becomingsubsequent talkers when they do so later).

Checks on subscribers in a group to establish whether or not they shouldbe intercepted can take place when a group call is set up (i.e. inquirywhether they wish to participate in the group call) and/or cyclically.The check also expediently includes subscribers in the group joining agroup call connection later (after the call has been set up). As soon asa subscriber enters the “emission range” of this/their group or isclassified as to be intercepted, all voice data transmitted via thegroup call connection can be intercepted although it does not have tobe.

It can be established whether subscribers in a group are to beintercepted based on a comparison of their current location (e.g. bymeans of a LUP Location Update Ticket) and a predefined spatial servicearea for a group call (in particular in the form of a Voice BroadcastCall), in which service area voice data of the group call (in particularin the case of a Voice Broadcast Service) is transmitted or can betransmitted according to a default, such that (in particular in the caseof a Voice Broadcast Call) a group is only intercepted, if a subscriberis located in the service area of the Voice Broadcast Call provided for,so there may be no need to ask the subscriber whether or not they wishto join the call.

Very efficient identification of subscribers participating actively in agroup call (by means of a connection to a traffic channel for voicedata) is in particular possible, in that a signaling message (inparticular an uplink access request message) is sent to one or all thesubscribers in a group for which a group call is possible (in particularin an uplink request message on a voice group call downlink), whereuponthe subscribers in the group call identify themselves (for example bymeans of an IMSI/MSISDN in a response) if they are in transmission range(and in some instances if they are interested in the group call and/orare activated).

If there is a change of speaker in a group (in which generally only onesubscriber can be the speaker), the new speaker can be prompted by meansof a signaling message to state their identity (in a signaling message),before they become the speaker, whereupon it can be checked whether saidspeaker should be intercepted.

Voice data to be intercepted is expediently copied in a switching deviceetc. and sent as CC (Content of Communication) to a (generallygovernment) interception center. Descriptive information relating tosaid communication can be provided in the IRI (Interception RelatedInformation) packet.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention will emerge from the claims and thedescription which follows of an exemplary embodiment.

FIG. 1 shows a schematic representation of a known group call,

FIG. 2 shows a schematic representation of a known VGCS group callaccording to 3GPPTS42.068,

FIG. 3 shows a schematic representation of a known VBS group callaccording to 3GPPTS42.069,

FIG. 4 shows a group call register GCR,

FIG. 5 shows a claimed monitoring situation with anintercepter/dispatcher,

FIG. 6 shows a claimed monitoring situation by means of group call IDmonitoring in a switching device,

FIG. 7 shows a change of speaker during monitoring of a group call.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an example of a group call (Voice Group Call Service/VoiceBroadcast Service) in a mobile radio network. The general structure of amobile radio network is known to the person skilled in the art, forexample for a GSM network or 3GPP network from www.etsi.org. In theexample in FIG. 1 there is at least one traffic channel respectivelybetween each of the mobile radio stations A, B, C, D and a switchingdevice (shown as a circle) (MSC/SGSN/GGSN/entire core net, etc.) andbetween dispatchers E, F and the switching device. In the example inFIG. 1 the subscriber A (the mobile station A) is speaking, while themobile stations B, C, D and the dispatchers E, F simply listen.Therefore the subscriber A requires at least one traffic channel in theuplink direction and the subscribers B-F require at least one trafficchannel in the downlink direction.

FIG. 2 shows an example of a group call connection in the form of aVoice Group Call Service VGCS according to 3GPPTS42.068 (according towhich specification there is provision for speaking, listening, speakingand listening subscribers as well as dispatchers (able to speak withoutvoice authorization tokens)), which defines for a group (VGCS1)respectively a group address a (group identity of the group for theswitching devices), a group call area I and the identities ofdispatchers x for this group. The group addresses a therefore indicateall the service subscribers, who are potential subscribers in a groupcall connection and can be prompted by a signaling to participate in thegroup call connection before a group call connection is set up. A groupcall area I can define a geographical area such as one or a plurality ofradio cells or radio cell sectors. Dispatchers x are potentialsubscribers (i.e. according to the invention also an interceptionequipment), who can for example also be included in group callconnections via GSM or external networks irrespective of their location.

If a group call VGCS according to 3GPPTS42.068 is set up, thesubscribers in the group call are asked whether they wish to participateand those who wish to participate are connected together by means oftraffic channels in the uplink and/or downlink direction, with thepossibility of providing for changing speaker roles.

FIG. 3 shows a group call connection in the form of a Voice BroadcastService VBS according to 3GPPTS42.069 for example. With this servicevoice data is only transmitted in predefined areas (Group Call Areas Ietc.), in some instances only if at least one subscriber from asubscriber list for a group (e.g. A) is located in the area (Group CallArea) of the group call.

FIG. 4 shows a Group Call Register GCR, in which data relating to groupcalls, such as the group call area, potential subscribers in the groupcall, dispatchers, etc., can be stored, the GCR being able to beaccessed by anchor devices, MSCs and/or other switching devices ortelecommunication network components.

FIG. 5 shows a claimed monitoring of a group call, in which a monitoringdevice (MC=Monitoring Center) is included in a group call as asubscriber (expediently without the subscribers being informed of this),in particular as a dispatcher, as known per se from 3GPPTS42.069 or3GPPTS42.068 (dispatcher: subscriber connected via a mobile radionetwork or fixed network, who can speak in some instances even withoutbeing assigned a speaker role and who can receive). As a result thisinterception equipment MC in FIG. 5 receives all voice data transmittedvia voice channels from or to one of the (active) subscribers A-F in thegroup call connection via a switching device or switching devices (shownas a circle in the center) and can forward this to an interceptioncenter, for example of a government office.

FIG. 6 shows a further claimed example of an interception equipment, inwhich voice data transmitted via a switching device(“MSC”/GGSN/SGSN/etc.) between the subscribers A-F (or A-D) in the groupcall connection (group call) is copied and transmitted as a copy (oralternatively as the original) from a switching device to a monitoringdevice MC, which can forward it to a government interception center.

FIG. 7 shows a change of speaker during monitoring of a group call,which can be the trigger for determining the identity of the speaker andchecking whether said speaker is to be monitored (and therefore whetherthe voice data and/or other data (e.g. image data) of the group callconnection is to be intercepted). Details relating to the“administrative” process of checking (before active monitoring) whethermonitoring (interception) should take place:

If the voice data etc. transmitted for a specific group call ID is to bemonitored in a switching device, it is expedient to identify therespective group IDs (statically, e.g. at the start, or dynamically attime intervals). A subscriber register (VLR/HLR) determines theassociation of a subscriber with the group IDs of groups. Subscriberregisters can in particular be home location registers (HLR) of a mobileradio network in respect of subscribers registered there. In the case ofroaming subscribers (telecommunicating in mobile radio networks otherthan their home network) it is possible to check group association invisitor location registers (VLR) visited by subscribers.

These group IDs (group identity data) could be deselected by asubscriber on the SIM, in other words the subscriber is a member of saidgroup in the HLR and on the SIM but does not listen to the calls(therefore does not necessarily have to be monitored). It is thereforeexpedient to identify the “active” (listening and/or speaking)subscribers for the group IDs (e.g. at the start of a group connectionand/or dynamically at time intervals:

-   -   In the home location register HLR all entries corresponding to        the group ID to be monitored are searched accordingly and        identified as optional partners and supplied to the monitoring        devices as IRI (Intercept Related Information) at the HI2        (Handover Interface 2).    -   it is also possible to search for the corresponding group IDs in        the visitor location registers VLR (only possible in the        corresponding PLMN) visited by subscribers in the        telecommunication network, as in the HLR (with the above        restriction).    -   The dispatchers input as subscribers in a group call are read        from the register GCR and supplied to an interception center as        IRI via an HI2 interface.

An investigation of the existing connections is optional, as this isgenerally not prescribed for CS connections. A switching device (MSC)uses the status flag indication in the GCR to determine the current(ongoing) group/broadcast calls with the defined group IDs. Thisinformation is supplied via HI2/IRI. If there are two active groups, thepriority indicators can be used to decide the group in which themonitored subscriber is participating. If two groups of equal priorityshould be active, it is not possible to decide the group in which themonitored subscriber is listening. Notification of both groups ishowever possible.

Verification whether a subscriber is to be intercepted: A switchingdevice (MSC) sends an uplink access request in an uplink free message onthe voice group call channel downlink. The mobile stations(=subscribers) should send back an uplink access request including datarepresenting their identity (IMSI/MSISDN). This allows the requiredsubscriber to be identified. It can then be decided whether monitoringshould be terminated (no monitored parties participating in the groupcall connection) or continued, as a monitored party may participatelater.

Identification of a Subsequent Talker:

A subsequent talker (a subscriber who later participates in an alreadyexisting group call connection) should send their IMSI/MSISDN to atelecommunication network, when they wish to have an uplink (to transmitthe voice data they are sending). The message uplink request shouldthereby include identity details. It can then be decided whethermonitoring should be terminated (no monitored parties participating inthe group call connection) or continued, as a monitored party mayparticipate later.

1. Method for intercepting subscribers in a telecommunication network,characterized in that it is determined for the subscriber (A) of a groupcall connection initiating the setting up of a group call connectionbetween more than two subscribers (A-F) and for further subscribers(B-D/B-F) in the group call connection, whether there is provision forinterception and at least one of the subscribers (B-F), and if there isprovision for intercepting at least one (B) of the subscribers(B-D/B-F), voice data transmitted via the group call connection issupplied to an interception equipment (MC).
 2. Method according to claim1, characterized in that in a switching center (MSC) voice data to beintercepted is selected from voice data to be transmitted by theswitching center (MSC) based on information representing the identify(group call ID) of the group connection and this voice data to beintercepted is transmitted to a monitoring device (MC/LIA).
 3. Methodaccording to claim 1, characterized in that all the voice datatransmitted in a group call connection is intercepted, if at least onesubscriber in the group call connection is to be monitored.
 4. Methodaccording to claim 1, characterized in that an interception equipment isdefined as a subscriber (dispatcher) in the group call connection,receiving all the voice data transmitted via the group call connection,preferably without this being signaled to the other subscribers in thegroup call connection.
 5. Method according to claim 1, characterized inthat a check is carried out for subscribers in a group call connectionwhether they are to be intercepted by interrogating a subscriberregister (HLR/VLR) of a mobile radio network.
 6. Method according toclaim 1, characterized in that subscribers to be intercepted or theirgroup call connection are only monitored, if they have requested thereceipt of voice data and/or the transmission of voice data for a groupcall connection.
 7. Method according to claim 1, characterized in thatthe check whether subscribers are to be intercepted takes place when agroup call is set up and/or repeatedly at time intervals.
 8. Methodaccording to claim 1, characterized in that the check whether asubscriber is to be intercepted also takes place when a furthersubscriber joins an existing group call connection later.
 9. Methodaccording to claim 1, characterized in that subscribers in a group callconnection to be intercepted are subscribers, for whom a comparison oftheir current location (LUP) and a spatial service area (group callarea) in which voice data of the group call is transmitted, aspredefined for a group call, shows that the subscriber can receive or isreceiving voice data based on their current location.
 10. Methodaccording to claim 1, characterized in that the subscribers in a groupor a group call are prompted to identify themselves (IMSI/MSISDN) by ameans of a signaling message to a subscriber (uplink free message/uplinkaccess request), to determine whether a subscriber to be monitored isparticipating in a group call connection.
 11. Method according to claim1, characterized in that voice data of a group call connection is onlyintercepted, if a subscriber to be intercepted is participating in agroup call connection.
 12. Method according to claim 1, characterized inthat if the speaker in a group call connection changes, the new speakeris prompted to relay their identity (FIG. 7), before they become the newspeaker, and that their identity is relayed and/or it is determinedwhether they should be monitored.
 13. Method according to claim 1,characterized in that intercepted voice data is sent in an IRI packet toan interception center.
 14. Method according to claim 1, characterizedin that the telecommunication network is a mobile radio network,preferably a cellular mobile radio network, and that subscribers aremobile stations.
 15. Method according to claim 1, characterized in thata group call is a voice broadcast or a voice group call.
 16. Methodaccording to claim 1, characterized in that it is also determined forthe subscriber (A) initiating the setting up of a group call connection,whether there is provision for intercepting said subscriber (A) and, ifthere is provision for intercepting said subscriber (A), voice datatransmitted via the group connection is supplied to an interceptioncenter (MC).
 17. Device for implementing the method according toclaim
 1. 18. Device, in particular according to claim 17, characterizedin that the device (MSC) is configured to send copies of voice databased on a group connection identity (group call ID) to an interceptioncenter (MC).
 19. Device according to claim 17, characterized in that thedevice (MSC) is configured to send voice data sent via the group callconnection to an interception equipment as a subscriber in a group callconnection to be monitored, in particular thereby to define theinterception equipment (MC) as a dispatcher.